I’m sorry for posting this post. 1 minute after posted I found the solution.
But perhaps there are others which it can helpfull.
I have the Problem, that I get the “cannot communicate with proxy” error.
It was a misconfigured Firewall. I make the rules with Interface bindings, and here I make a misstake.
You can please remove or delete this post. I don’t found the trash icon.
Sorry for your time.